New Horizons in Cosmology with Spectral Distortions of the Cosmic Microwave Background

TL;DR

Spectral distortions of the CMB offer a promising avenue for probing fundamental processes in the early universe, with existing technology capable of advancing our understanding of cosmology and new physics.

Contribution

This white paper emphasizes the potential of spectral distortion measurements of the CMB to test cosmological models and explore new physics, proposing dedicated experiments to detect standard signals.

Findings

Spectral distortions can reveal processes like inflation, recombination, and dark matter interactions.

Existing technology can achieve precision spectroscopy to detect expected distortion signals.

Dedicated experiments could transform upper limits into definitive detections.

Abstract

Voyage 2050 White Paper highlighting the unique science opportunities using spectral distortions of the cosmic microwave background (CMB). CMB spectral distortions probe many processes throughout the history of the Universe. Precision spectroscopy, possible with existing technology, would provide key tests for processes expected within the cosmological standard model and open an enormous discovery space to new physics. This offers unique scientific opportunities for furthering our understanding of inflation, recombination, reionization and structure formation as well as dark matter and particle physics. A dedicated experimental approach could open this new window to the early Universe in the decades to come, allowing us to turn the long-standing upper distortion limits obtained with COBE/FIRAS some 25 years ago into clear detections of the expected standard distortion signals.